All Questions
Tagged with reversibility quantum-mechanics
23 questions
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Given a viably physical (isolated), quantum many body Hamiltonian, does an initial state of a superposition of energy eigenstates ever thermalize?
Given a viably physical, quantum many body Hamiltonian of a isolated system, if initially a state is prepared which is a superposition of energy eigenstates in an interval centered at E and E', not at ...
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Is stochasticity totally incompatible with current theories of conservation of information in quantum physics?
Most physicists accept the unitarity principle of the universe, according to which the state of a system at any given time must determine its state at any other time (information is never lost, ...
- 81
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Time's Arrow and QM
Something puzzles me. It is sometimes said that the fundamental equations of physics are time-reversible, creating the problem of time's arrow. But... isn't Schrodinger's wave equation time-dependent? ...
- 31
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How do we physically reverse a classical wavepacket?
Imagine a classical dispersive Gaussian wavepacket (GW). In a wonderful answer by @Qmechanic, to this question (who seems to do much tagging these days, with an occasional well-aimed-and-hit answer), ...
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Is Hong–Ou–Mandel effect reversible?
According to Hong–Ou–Mandel effect, two photons coming from the different ports will output by the same port with 2 photons since the cross term is canceled by a 1:1 beamsplitter. Since "light ...
- 181
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Can a non-unitary free operation on a resource state be reversed?
Under the framework of resource theories like entanglement, asymmetry, athermaility, etc, a set of operations $\mathcal{O} \subset \mathcal{B}(\mathcal{H})$ is chosen (e.g., LOCC) due to physical ...
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Reversibility of Physical Process : QM vs CM
It is often stated that the processes in quantum mechanics are reversible as they follow the Schrodinger's Equation : $$ - \frac{\hbar^2}{2m} \nabla^2 \Psi(x,t) + V(x,t)\ \Psi(x,t) = i \hbar\ \frac{\...
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How does the reversibility of physics interact with nuclear fission?
The laws of physics are reversible and quantum information is never destroyed.
Given this, how do I time reverse the $U_{235}$ fission reaction, n which
${}^1_0n + {}^{235}_{92}U \rightarrow {}^{141}_{...
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Irreversibility as an artificial concept and relationship with quantum mechanics
In my statistical physics classes we are following the book Statistical physics of particles - by Mehren Kardar and we were viewing the derivation of the boltzmann equation and irreversibility . ...
- 669
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Is there experimental evidence for the irreversibility of the collapse of the state of a system due to a measurement?
It has been pointed out by one of my professors that, in quantum mechanics,
the collapse of the state of the system by measurement is not
time-reversible, i.e once the system collapses due to a ...
- 2,313
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Why is quantum mechanics reversible?
"Quantum mechanics is reversible" this statement is everywhere, some even said it's just an observed fact about the universe. I can't find a layman explanation or example why is it reversible?
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How are the laws of physics reversible?
I am watching a course on quantum mechanics from Stanford university. Today I heard that the tutor said:
Laws of physics are reversible,
Information is never lost.
what does it mean ...
- 45
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Reversibility in physics
Is our present understanding of the laws of physics fundamentally reversible? Is easy to see that in classical mechanic this is correct, but I can't see it in quantum mechanic. I know that ...
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Reverisbility of pysical laws (perpetual motion of atoms) proves the atomic/quantum hypothesis [closed]
As I understand, the atomic hypothesis and quantum theory says that we cannot divide the matter infinitely. Atoms were discovered 100 years ago but why are they indivisible apart? It is said that they ...
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Is heat death reversible by thermal or quantum fluctuations given an infinite time?
I'm new here, so apologies if the question doesn't sound meaningful considering what physics is supposed to answer. I don't have a physics or mathematics background, but I did learn a few things about ...
- 452
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Is an interaction-free measurement an irreversible process?
From what I've understood from reading different online sources including PSE*, measurements in quantum mechanics are generally argued to be irreversible (at least, when a macroscopic measuring device ...
- 2,493
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What experiment supports the axiom that quantum operations are reversible?
Among the axioms of quantum mechanics there is one axiom that says transformations of a quantum state need to be continuous, linear, and reversible (and this together with the other axioms results in ...
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Unitarity of a transformation, and reversibility, imply one another?
Are these concepts equivalent? And if not, which one implies the other one?
A transformation $\hat U$ is unitary when $\hat U^{-1} = \hat U^{\dagger}$.
A reversible transformation $\hat A$ admits an ...
- 6,920
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Change in Shannon entropy of a quantum circuit of Hadamard gate and a loop
The following Q&A about reversible computing is available here. It has listed a number of practical scenarios where a reversible circuit can still be dissipating heat. Let's assume that none of ...
- 238
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What is the nature of the correspondence between unitary operators and reversible change?
Why does the formalism of QM represent reversible changes (eg the time evolution operator, quantum gates, etc) with unitary operators?
To put it another way, can it be shown that unitary ...
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Irreversibility and the Fermi golden rule
When a quantum system is perturbatively coupled to a continuum of states, one uses the Fermi's golden rule to compute the rate of transition form an initial state to a set of states contained in an ...
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Hawking radiation and reversibility
It's often said that, as long as the information that fell into a black hole comes out eventually in the Hawking radiation (by whatever means), pure states remain pure rather than evolving into mixed ...
- 2,482
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Heuristics for definitions of open and closed quantum dynamics
I've been reading some of the literature on "open quantum systems" and it looks like the following physical interpretations are made:
Reversible dynamics of a closed quantum system are represented by ...
Dave Gaebler